* Distress signal picked up early on Friday
* EU Navy says similar yacht spotted near Somali coast
* Seychelles coastguard, foreign navies search for yacht
(Adds yacht spotted by EU forces)
By Abdi Guled
MOGADISHU, Oct 27 Somali pirates said on Tuesday they had seized a yacht in the Indian Ocean with a British couple aboard and were taking the vessel to the Horn of Africa nation with a view to demanding a ransom.
The European Union counter-piracy force operating in the Indian Ocean said it had spotted a yacht 200 nautical miles (370 km) from the Somali coast and they were trying to establish if it was the vessel that sent out a distress call early on Friday.
"What we can't confirm is if it is the same sailing yacht which we are looking for. That needs further investigation. The reason is that it is dark in the area," Lieutenant Commander Daniel Auwermann, spokesman for EU Navfor told Reuters.
The Seychelles coastguard said it dispatched aircraft to search for the yacht after receiving a distress signal on Friday and that naval forces from the NATO alliance, European Union and United States, among others, had joined the search.
The Britons, Paul and Rachel Chandler, both in their fifties, left the Seychelles aboard their 38-foot yacht, Lynn Rival, on Oct. 22 and were believed to be sailing towards the east African coast.
"The British couple are in our hands now. We captured them as they were touring in the Indian Ocean," a pirate called Hassan told Reuters. He said the two captives were healthy and ransom demands would follow.
Lieutenant Colonel Michael Rosette, who is in charge of the Seychelles coastguard, said on Tuesday it had no confirmation the yacht had been taken by pirates, but the probability of a highjacking was high.
Maritime security groups warned in May of a surge in the number of pirate "mother ships" operating in the Seychelles archipelago's expansive territorial waters.
The pirates typically use "mother ships" to sail hundreds of miles to sea and then launch attacks in small skiffs, armed with assault rifles and rocket-propelled grenade launchers.
The gangs -- some made up of former Somali fisherman angered by the presence of foreign fishing vessels in their waters -- have made tens of millions of dollars in ransoms.
GUNMEN PLAGUE SHIPPING LANES
The U.S. military said in August it would be deploying unmanned reconnaissance aircraft above the Seychelles to bolster anti-piracy efforts.
Pirates have plagued busy shipping lanes off the coast of Somalia for several years. Foreign navies have warships in the area to try and prevent hijacks, but the sea gangs have started to hunt for ships far into the Indian Ocean.
In Britain, Chandler family members expressed dismay over the reported seizure.
"You never believe it is going to be one of those things that happens to your family," the couple's niece Leah Mickleborough told BBC radio.
"All of us as a family are extremely upset by what has happened. We are very distressed and it is such an emotional thing and such a horrible thing to be experiencing," she said.
Rachel Chandler's brother Stephen Collett told ITV News there was little prospect any kidnappers would get a ransom.
"I think everything they've got is invested in their boat, so if they have been captured then the pirates have got the boat, which is as much as they're going to find really."
A sailors' forum on the Internet said the distress signal was picked up at 0133 GMT on Friday and that the vessel was 60 nautical miles (111 km) from Victoria, the Seychelles' capital.
In their most audacious attack, pirates hijacked a Saudi supertanker with $100 million worth of oil on board in November last year. It was released after a $3 million ransom was paid.
While there was a relative lull in hijackings in Indian Ocean waters during the middle of 2009 because of monsoon rains, the number of attacks has increased in the past month.
Somali pirates seized a Spanish tuna fishing vessel early in October and a Chinese bulk carrier later in the month. A number of other unsuccessful attacks have been reported. (Additional reporting by George Thande in Victoria, Richard Lough in Antananarivo, Bate Felix in Brussels and Peter Griffiths in London; Writing by David Clarke; Editing by Jon Boyle)